Hyperlink works - Html Form with a Submit button doesn't

Question

I have a PHP script that pushes the headers to allow a file to download. This script works fine when it called via a hyperlink or through the browser using link. This is how it looks like:

<a href="download.php?file=test.mp3&properFilename=Testing File">Download</a>

I want this to be a button (sbumit) instead, so I did this:

<form action="download.php?file=test.mp3&properFilename=Testing File" method="get">
<input type="submit" value="Download Audio" name="download"/>
</form>

However, this doesn't work. When I click on it. It initiates the download dialog box but the filename is empty. It shows file name as ".mp3" (without quotes)! That same link via the hyperlink shows the exact file name "Testing File". Why is this?? Here is the PHP snippet concerned:

$filename = '../'.$_GET['file'];
$properFilename = $_GET['properFilename'].'.mp3';

header("Content-Disposition: attachment; filename=\"".basename($properFilename)."\";" );
header("Content-Transfer-Encoding: binary");
header("Content-Length: ".filesize($filename));
readfile("$filename");
exit();

Thank you for any help. This has been driving me mad all day and night!!!

Answer 1

I think that the action url it's been urlencoded, and the hard-coded GET parameters are not sent.

You can try to set the action url simply to download.php and have two hidden fields containing the "file" and "properFilename" parameters, like this:

<form action="download.php" method="GET">
  <input type="submit" value="Download Audio" name="download"/>
  <input type="hidden" name="file" value="test.mp3" />
  <input type="hidden" name="properFilename" value="Testing File" />
</form>

Or you can use a input type="button", even without the form:

<input type="button" 
      onclick="location.href='download.php?file=test.mp3&properFilename=Testing File';" 
      value="Download"/>

Or an image button:

<a href="download.php?file=test.mp3&properFilename=Testing File">
   <img src="IMAGE_BUTTON_HERE" />
</a>

Answer 2

Instead of using <input type='button'> as CMS suggests, you can also use the button element (which is actually the semantic correct one here since your not in a form)

<button onclick="document.location = 'bla.php?f=vars'">Download</button>

Even better would be off course be to move the onclick event out of the button into a seperate javascript file.